Printed circuit board with wiring pattern formed thereon by screen printing and process for manufacturing the same

ABSTRACT

A printed circuit board having an insulating board and a plurality of wiring patterns formed over the insulating board by screen printing and provided with first conductive pattern bent parts and wiring parts linked to the first conductive pattern bent parts. A pattern width in the first conductive pattern bent parts is greater than that of the patterns of those of the wiring parts positioned close to and on both sides of the first conductive pattern bent parts.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional application of U.S. patentapplication Ser. No. 10/037,733 filed on Jan. 2, 2002 entitled “PRINTEDCIRCUIT BOARD WITH WIRING PATTERN FORMED THEREON BY SCREEN PRINTING ANDPROCESS FOR MANUFACTURING THE SAME” by Akihiro KUSAKA (Attorney DocketNo. ALPSP062), from which priority is claimed under 35 U.S.C. §120. Thisapplication is incorporated herein by reference in its entirety for allpurposes.

[0002] The present application is related to U.S. patent application No.______ filed concurrently with the present application entitled “PRINTEDCIRCUIT BOARD WITH WIRING PATTERN FORMED THEREON BY SCREEN PRINTING ANDPROCESS FOR MANUFACTURING THE SAME” by Akihiro KUSAKA (Attorney DocketNo. ALPSP062D1).

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention relates to a printed circuit board that canbe suitably used in electronic devices including video cameras.

[0005] 2. Description of the Prior Art

[0006] To describe a printed circuit board according to the prior artand its manufacturing method with reference to FIG. 9 through FIG. 12,an insulating board 21 consisting of a flexible substrate or the likehas a rectangular base 22 provided with fixed contacts (not shown) orthe like and a drawn part 23 having a substantially L-shaped overallform.

[0007] This drawn part 23 is substantially L-shaped to stay away fromelectrical parts or (not shown) or fitting members (not shown) arrangedwithin the electronic device, and has insulating board angled parts 23 abent in an L shape or the like, cables 23 b connected to both sides of,and formed in a width equal to, these insulating board angled parts 23a, and leaders 23 c formed at an end of the cables 23 b.

[0008] A plurality of wiring patterns 24 made of silver have conductivepattern bent parts 24 a shaped in an L or the like, linear wiring parts24 b connected to both ends of, and having a pattern with equal widthto, these conductive pattern bent parts 24 a, and linear connectingparts 24 c provided at an end of the wiring parts 24 b.

[0009] The plurality of wiring patterns 24 are formed in parallel byscreen printing over the drawn part 23 in a state wherein the conductivepattern bent parts 24 a are arranged over the insulating board angledparts 23 a of the drawn part 23 of the insulating board 21, the wiringparts 24 b are arranged over the cables 23 b and the base 22, andfurther the connecting parts 24 c are arranged over the leaders 23 c.

[0010] The wiring parts 24 b formed over the base 22 are connected tofixed contacts (not shown) formed of an electroconductive pattern overthe base 22.

[0011] The wiring patterns 24 are so designed that the pitch of thepatterns in the conductive pattern bent parts 24 a be equal to the pitchof the patterns of the wiring parts 24 b positioned close to and on bothsides of the conductive pattern bent parts 24 a, and that the gap widthbetween the conductive pattern bent parts 24 a be equal to the gap widthbetween the wiring parts 24 b positioned close to and on both sides ofthe conductive pattern bent parts 24 a.

[0012] On such a printed circuit board, the connecting parts 24 cprovided in leaders 23 c are connected to a connector (not shown), sothat a current from outside is entered into the printed circuit boardvia the connecting parts 24 c or a current from the printed circuitboard is supplied outside via the connecting parts 24 c.

[0013] By a manufacturing method for such a printed circuit boardaccording to the prior art by screen printing, as shown in FIG. 11,after the insulating board 21 is mounted on a mount 25, a meshedprinting mask 26 is mounted over the insulating board 21.

[0014] Next, after painting or otherwise applying silver paste 27 overthe printing mask 26, a squeegee 28 is moved in the direction of arrow Ato form the plurality of wiring patterns 24 over the insulating board 21by printing.

[0015] Thus, as shown in FIG. 9 and FIG. 10, the squeegee 28 is moved inthe direction of arrow A, and first the conductive pattern bent parts 24a are formed by printing, followed by the formation of the wiring parts24 b by printing.

[0016] The reason why the squeegee 28 is moved in the direction of arrowA is that the formation of the wiring patterns 24 by printing in a statein which their orthogonal intersections with the squeegee 28 areminimized results in minimization of the running or blurring ofpatterns. In particular, minimization of orthogonal intersectionsbetween the wiring parts 24 b having large pattern areas and the movingpath of the squeegee 28 serves to reduce the running or blurring of thepatterns of the wiring parts 24 b.

[0017] However, while the conductive pattern bent parts 24 a are printedearlier in an orthogonally crossing state than the wiring parts 24 b bythe movement of the squeegee 28 in the direction of arrow A, the silverpaste 27 flows from the peak toward the trough of the ink permeatingpart of the printing mask 26 for the formation of the conductive patternbent parts 24 a during the printing of these conductive pattern bentparts 24 a.

[0018] If, then, the printing conditions lose balance, slight quantitiesof the silver paste 27 may get caught between the printing mask 26 andthe insulating board 21 in corners of the trough of the ink permeatingpart, and create running parts 24 d as shown in FIG. 10.

[0019] As a result, these running parts 24 d would often short-circuitthe wiring patterns 24 among themselves.

[0020] Or if in the conventional printed circuit board and itsmanufacturing method the squeegee 28 is moved in the direction of arrowB first to form the connecting parts 24 c by printing and then theconductive pattern bent parts 24 a are formed by printing after thewiring parts 24 b are printed as shown in FIG. 12, blurred parts 24 e ofthe silver paste 27 (see FIG. 12) may be caused to occur and possiblyinvite wire breaking in the conductive pattern bent parts 24 a bystagnant air or the like gathering in the corners at the top of the inkpermeating part of the printing mask 26 for forming the conductivepattern bent parts 24 a.

[0021] As printed circuit boards are required to be reduced in sizealong with the advance in the size compression of electronic devices inwhich they are to be used, the wiring patterns 24 are more narrowlyspaced between one another and also reduced in width, running parts 24 dand blurred parts 24 e would give rise to the risks of short-circuitingand wire breaking in the resultant narrower conductive pattern bentparts 24 a.

[0022] In the conventional printed circuit board and its manufacturingmethod, since gaps between the conductive pattern bent parts 24 a of thewiring patterns 24 are designed to be as wide as gaps between the wiringparts 24 b positioned near their two sides and screen printing iscarried out in the direction of arrow A, running parts 24 d arise in thetrough of the conductive pattern bent parts 24 a, making the wiringpatterns 24 susceptible to short-circuiting between each other.

[0023] Or if screen printing is carried out in the direction of arrow B,blurred parts 24 e may arise at the top of the conductive pattern bentparts 24 a, giving rise to the risk of inviting wire breaking.

SUMMARY OF THE INVENTION

[0024] In view of these problems, the present invention is intended toprovide a more reliable printed circuit board less susceptible toshort-circuiting or wire breaking in the conductive pattern bent partsof wiring patterns, and its manufacturing method.

[0025] According to a first aspect of the invention, the problems notedabove are solved with a configuration having an insulating board and aplurality of wiring patterns formed over this insulating board by screenprinting and provided with first conductive pattern bent parts andwiring parts linked to these first conductive pattern bent parts, gapsbetween adjoining first conductive pattern bent parts are formed widerthan those between those of the wiring parts positioned close to and onboth sides of the first conductive pattern bent parts.

[0026] According to a second aspect of the invention, a pitch ofpatterns in the first conductive pattern bent parts is formed greaterthan that of the patterns of those of the wiring parts positioned closeto and on both sides of the first conductive pattern bent parts.

[0027] According to a third aspect of the invention, a pattern width inthe first conductive pattern bent parts is greater than that of thepatterns of those of the wiring parts positioned close to and on bothsides of the first conductive pattern bent parts.

[0028] According to a fourth aspect of the invention, wiring patternsare screen-printed in such a printing direction that the firstconductive pattern bent parts are formed by printing earlier than thewiring parts.

[0029] According to a fifth aspect of the invention, the insulatingboard has first insulating board angled parts and cables linked to bothsides of these first insulating board angled parts, wherein a width ofthe first insulating board angled parts is formed greater than that ofthe cables, the first conductive pattern bent parts are positioned inthe first insulating board angled parts, and a plurality of the wiringpatterns are provided in a state in which the wiring parts arepositioned in the cables.

[0030] According to a sixth aspect of the invention, the wiring patternshave second conductive pattern bent parts bent in a direction reverse tothe first conductive pattern bent parts and wiring parts linked to thesesecond conductive pattern bent parts, wherein a pattern width in thesesecond conductive pattern bent parts is formed greater than that ofthose of the wiring parts positioned close to and on both sides of thesecond conductive pattern bent parts.

[0031] According to a seventh aspect of the invention, the wiringpatterns are screen-printed in such a printing direction that the secondconductive pattern bent parts are formed by printing after the wiringparts linked to the second conductive pattern bent parts are formed byprinting.

[0032] According to an eighth aspect of the invention, a pitch of thepatterns in the second conductive pattern bent parts is formed greaterthan that of the patterns of those of the wiring parts positioned closeto and on both sides of the second conductive pattern bent parts, andgaps between adjoining ones of the second conductive pattern bent partsare formed wider than those between those of the wiring parts positionedclose to and on both sides of the second conductive pattern bent parts.

[0033] According to a ninth aspect of the invention, the insulatingboard has second insulating board angled parts bent in a directionreverse to the first insulating board angled parts and cables linked toboth sides of these second insulating board angled parts, wherein awidth of the second insulating board angled parts is formed greater thanthat of the cables, and a plurality of wiring patterns are provided in astate in which the second conductive pattern bent parts are positionedin the second insulating board angled parts and the wiring parts arepositioned in the cables.

[0034] According to a tenth aspect of the invention, the firstinsulating board angled parts and the second insulating board angledparts bent in a direction reverse to these first insulating board angledparts are formed adjoining each other, linked by the cables.

[0035] According to an eleventh aspect of the invention, there isprovided a printed circuit board manufacturing method provided with aplurality of wiring patterns having first conductive pattern bent partsand wiring parts linked to these first conductive pattern bent parts,wherein the wiring patterns are screen-printed on an insulating board insuch a printing direction that the first conductive pattern bent partsare formed by printing earlier than the wiring parts, and the gapsbetween adjoining ones of the first conductive pattern bent parts areformed wider than those between those of the wiring parts positionedclose to and on both sides of the first conductive pattern bent parts.

[0036] According to a twelfth aspect of the invention, the pitch ofpatterns in the first conductive pattern bent parts is formed greaterthan that of the patterns of those of the wiring parts positioned closeto and on both sides of the first conductive pattern bent parts.

[0037] According to a thirteenth aspect of the invention, the wiringpatterns have second conductive pattern bent parts bent in a directionreverse to the first conductive pattern bent parts and wiring partslinked to these second conductive pattern bent parts, wherein the wiringpatterns are formed by screen-printing the wiring parts on theinsulating board in such a printing direction that the wiring partslinked to the second conductive pattern bent parts are formed byprinting earlier than the second conductive pattern bent parts so thatthe pattern width in these second conductive pattern bent parts isformed greater than that of those of the wiring parts positioned closeto and on both sides of the second conductive pattern bent parts.

[0038] According to a fourteenth aspect of the invention, there isprovided a printed circuit board manufacturing method wherein the pitchof patterns in the second conductive pattern bent parts is formedgreater than that of the patterns of those of the wiring partspositioned close to and on both sides of the second conductive patternbent parts.

[0039] According to a fifteenth aspect of the invention, there isprovided a printed circuit board manufacturing method wherein the firstconductive pattern bent parts and the second conductive pattern bentparts adjoining these first conductive pattern bent parts arescreen-printed on the insulating board in a state in which they arelinked by the wiring parts.

[0040] According to a sixteenth aspect of the invention, there isprovided a printed circuit board manufacturing method wherein aplurality of sets of the wiring patterns each consisting of the wiringpatterns provided with the first and second conductive pattern bentparts and the wiring parts are formed by screen printing over a largeinsulating base.

[0041] According to a seventeenth aspect of the invention, there isprovided a printed circuit board manufacturing method wherein theinsulating board having a set of the wiring patterns is formed out ofthe plurality of the wiring patterns by punching out of the largeinsulating base.

[0042] According to an eighteenth aspect of the invention, there isprovided a printed circuit board manufacturing method wherein the largeinsulating base is punched along the first and second conductive patternbent parts, the first and second conductive pattern bent parts arepositioned in first and second insulating board angled parts of theinsulating board, and the wiring parts are positioned in a cable linkedto the first and second insulating board angled parts of the insulatingboard.

[0043] According to a nineteenth aspect of the invention, there isprovided a printed circuit board manufacturing method wherein the firstand second insulating board angled parts are formed to have a greaterwidth than that of the cable by punching out of the large insulatingbase.

BRIEF DESCRIPTION OF THE DRAWINGS

[0044]FIG. 1 is a plan of the essential part of a printed circuit board,which is a first preferred embodiment of the present invention.

[0045]FIG. 2 is an expanded plan of the essential part of the printedcircuit board, which is the first embodiment of the invention.

[0046]FIG. 3 illustrates a manufacturing method for the printed circuitboard according to the invention.

[0047]FIG. 4 is a plan of the essential part of a printed circuit board,which is a second preferred embodiment of the invention.

[0048]FIG. 5 is an expanded plan of the essential part of the printedcircuit board, which is the second embodiment of the invention.

[0049]FIG. 6 is a plan of the essential part of a printed circuit board,which is a third preferred embodiment of the invention.

[0050]FIG. 7 is an expanded plan of the essential part of the printedcircuit board, which is the third embodiment of the invention.

[0051]FIG. 8 pertains to a printed circuit board manufacturing methodaccording to the invention, and in particular to the manufacture of theprinted circuit board, which is the third embodiment of the invention,from a large insulating base.

[0052]FIG. 9 is an overall plan of a printed circuit board according tothe prior art.

[0053]FIG. 10 is an expanded plan of the essential part of the printedcircuit board according to the prior art.

[0054]FIG. 11 pertains to the printed circuit board according to theprior art, and in particular to its manufacturing method.

[0055]FIG. 12 is another expanded plan of the essential part of theprinted circuit board according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] To explain the drawings illustrating the printed circuit boardand its manufacturing method according to the present invention, FIG. 1is a plan of the essential part of a printed circuit board, which is afirst preferred embodiment of the invention; FIG. 2 is an expanded planof the essential part of the printed circuit board, which is the firstembodiment of the invention; and FIG. 3 illustrates a manufacturingmethod for the printed circuit board according to the invention.

[0057]FIG. 4 is a plan of the essential part of a printed circuit board,which is a second preferred embodiment of the invention; FIG. 5, anexpanded plan of the essential part of the printed circuit board, whichis the second embodiment of the invention; FIG. 6, a plan of theessential part of a printed circuit board, which is a third preferredembodiment of the invention; FIG. 7, an expanded plan of the essentialpart of the printed circuit board, which is the third embodiment of theinvention; and FIG. 8 pertains to a printed circuit board manufacturingmethod according to the invention, and in particular to the manufactureof the printed circuit board, which is the third embodiment of theinvention, from a large insulating base.

[0058] To describe the printed circuit board and its manufacturingmethod according to the invention with reference to FIG. 1 through FIG.3, an insulating board 1 consisting of a flexible film or the like has arectangular base 2 provided with fixed contacts (not shown) and thelike, and a drawn part 3 having an L-shaped overall form.

[0059] This drawn part 3 is L-shaped to stay away from electrical parts(not shown) or fitting members (not shown) arranged within theelectronic device, and has insulating board angled parts 3 a bent in anL shape or the like, cables 3 b connected to both sides of, and formedin a width narrower than, these insulating board angled parts 3 a, andleaders 3 c formed at an end of the cables 3 b.

[0060] A plurality of wiring patterns 4 consisting of silver haveL-shaped conductive pattern bent parts 4 a, linear wiring parts 4 bconnected to both ends of these conductive pattern bent parts 4 a andequal in pattern width to the conductive pattern bent parts 4 a, andlinear connecting parts 4 c provided at an end of the wiring parts 4 b.

[0061] The pitch (the center-to-center distance between adjoiningpatterns) P1 of patterns in the conductive pattern bent parts 4 a isformed to be greater than the pitch P2 of patterns of those of thewiring parts 4 b positioned close to and on both sides of the conductivepattern bent parts 4 a, and the gap width (the distance between sideedges or adjoining patterns) G1 between the conductive pattern bentparts 4 a to be greater than the gap width G2 between the wiring parts 4b.

[0062] The plurality of wiring patterns 4 are disposed in parallel in astate in which the conductive pattern bent parts 4 a are arranged in thewide insulating board angled parts 3 a of the drawn part 3 of theinsulating board 1, the wiring parts 4 b are arranged in the cables 3 band the base 2, and the connecting parts 4 c are arranged in the leader3 c, and formed by screen printing of the same step on the drawn part 3.

[0063] The wiring parts 4 b formed over the base 2 are connected tofixed contacts (not shown) formed of electroconductive patterns over thebase 2.

[0064] This printed circuit board, with its connecting parts 4 cprovided in the leader 3 c being connected to a connector (not shown),allows a current from outside to be entered into it via the connectingparts 4 c or a current from it to be supplied outside via the connectingparts 4 c.

[0065] In the manufacturing method for this printed circuit board byscreen printing according to the invention, as illustrated in FIG. 3,after the insulating board 1 is mounted on the mount 5, a meshedprinting mask 6 is mounted over the insulating board 1.

[0066] Then, after painting or otherwise applying silver paste 7 overthe printing mask 6, a squeegee 8 is moved in the direction of arrow Ato form the plurality of wiring patterns 4 over the insulating board 1by printing.

[0067] Thus, as shown in FIG. 1 and FIG. 2, the squeegee 8 is moved inthe direction of arrow A, and first the conductive pattern bent parts 4a are formed by printing, followed by the formation of the wiring parts4 b by printing.

[0068] The reason why the squeegee 8 is moved in the direction of arrowA is that formation of the wiring patterns 4 by printing by minimizingtheir orthogonal intersections with the squeegee 8 results inminimization of the running or blurring of patterns. In particular,minimization of orthogonal intersections between the wiring parts 4 bhaving large pattern areas and the moving path of the squeegee 8 servesto reduce the running or blurring of patterns of the wiring parts 4 b.

[0069] However, while the conductive pattern bent parts 4 a are printedearlier in an orthogonally crossing state than the wiring parts 4 b bythe movement of the squeegee 8 in the direction of arrow A, the silverpaste 7 flows from the peak toward the trough of the ink permeating partof the printing mask 6 for the formation of the conductive pattern bentparts 4 a during the printing of these conductive pattern bent parts 4a.

[0070] Then, depending on the printing conditions including theviscosity of the silver paste 7 and the printing speed, slightquantities of the silver paste 7 may get caught between the printingmask 6 and the insulating board 1 in corners of the trough of the inkpermeating part, and create running parts 4 d as shown in FIG. 2.

[0071] As printed circuit boards are required to be reduced in sizealong with the advance in the size compression of electronic devices inwhich they are to be used, the wiring patterns 4 are more narrowlyspaced between one another and also reduced in width.

[0072] However, as the gap width G1 between the conductive pattern bentparts 4 a is formed greater than the gap width G2 of those of the wiringparts 4 b positioned on both sides and close to the conductive patternbent parts 4 a, it will be difficult for any running part 4 d that mayarise to invite short-circuiting between the wiring patterns 4.

[0073] Also, as the pattern pitch P1 in the conductive pattern bentparts 4 a is greater than the pattern pitch P2 in the wiring parts 4 bpositioned on both sides and close to the conductive pattern bent parts4 a, the pattern width in the conductive pattern bent part 4 a can beequalized to the pattern width of those of the wiring parts 4 bpositioned on both sides and close to the conductive pattern bent parts4 a.

[0074] Therefore, even if the gap width G1 between the conductivepattern bent parts 4 a is increased, there is no need to narrow thepattern width of the conductive pattern bent parts 4 a, resulting ineffective prevention of such troubles as increased resistance tocontinuity or wire breaking even if the pattern width is reduced.

[0075]FIG. 4 and FIG. 5 illustrate a second preferred embodiment of thepresent invention. In this second embodiment, the drawn part 3 isarranged by having the cables 3 b form second insulating board angledparts 3 d which are bent in a direction reverse to the insulating boardangled parts 3 a of the first embodiment and wider than the cables 3 b.

[0076] The wiring patterns 4 are bent further in an L shape from thosein the first embodiment, and are provided with conductive pattern bentparts (second conductive pattern bent parts) 4 e having a wider patternwidth W1, the linear wiring parts 4 b which are linked to both sides ofthese conductive pattern bent parts 4 e and have a narrower patternwidth W2 than the pattern width WI of the conductive pattern bent parts4 e, and the linear connecting parts 4 c provided at an end of thewiring parts 4 b.

[0077] Thus the pattern width WI in the conductive pattern bent parts 4e is formed greater than the pattern width W2 of those of the wiringparts 4 b positioned on both sides and close to the conductive patternbent parts 4 e.

[0078] The pattern pitch P1 in the conductive pattern bent parts 4 e isformed greater than the pattern pitch P2 of those of the wiring parts 4b positioned on both sides and close to the conductive pattern bentparts 4 e, and the gap width between the conductive pattern bent parts 4e is set equal to the gap width between those of the wiring parts 4 bpositioned on both sides and close to the conductive pattern bent parts4 e.

[0079] The plurality of wiring patterns 4 are disposed in parallel in astate in which the conductive pattern bent parts 4 e are arranged in theinsulating board angled parts 3 d of, the drawn part 3 of the insulatingboard 1, the wiring parts 4 b are arranged in the cables 3 b and theconnecting parts 4 c are arranged in the leader 3 c, and formed byscreen printing of the same step on the drawn part 3.

[0080] The conductive pattern bent parts 4 e are adjacently connectedvia the wiring parts 4 b to the conductive pattern bent parts 4 a formedin the insulating board angled parts 3 a, and other aspects of theconfiguration are the same as their respective counterparts in the firstembodiment. Therefore, the same constituent parts are assignedrespectively the same reference numbers, and their description isdispensed with.

[0081] The manufacturing method for this printed circuit board, which isthe second embodiment of the invention, by screen printing isaccomplished using an apparatus shown in FIG. 3. Thus the plurality ofwiring patterns 4 are formed by printing over the insulating board 1 bymoving the squeegee 8 in the direction of arrow A in FIG. 4 and FIG. 5.

[0082] Then, first the connecting parts 4 c are formed by printing, andnext the wiring parts 4 b are printed, followed by the formation of theconductive pattern bent parts 4 e by printing.

[0083] At the time of this printing, printing of the conductive patternbent parts 4 e which constitute part of the wiring patterns 4 is moresusceptible to the occurrence of blurred parts 4 f of the silver paste 7(see FIG. 5) or the like in the conductive pattern bent parts 4 eresulting from stagnant air or the like gathering in the corners at thetop of the ink permeating part of the printing mask 6 for forming theconductive pattern bent parts 4 e as the squeegee 8 begins to move in adirection substantially at a right angle to the direction of thepatterns after the wiring parts 4 b on both sides are printed.

[0084] As printed circuit boards are required to be reduced in sizealong with the advance in the size compression of electronic devices inwhich they are to be used, the wiring patterns 4 are more narrowlyspaced between one another and also reduced in width.

[0085] However, as the conductive pattern bent parts 4 e where theblurred parts 4 f or the like are apt to occur have a greater patternwidth, even if any blurred parts 4 f occurs in the conductive patternbent parts 4 e, there is more of the residual pattern in the conductivepattern bent parts 4 e, and accordingly no wire breaking will arise,resulting in enhanced reliability.

[0086] In the second embodiment of the invention show in FIG. 4 and FIG.5, while the movement of the squeegee 8 causes the conductive patternbent parts 4 a and the wiring parts 4 b to be formed by printing overthe insulating board angled parts 3 a and the cables 3 b positioned onthe side of these insulating board angled parts 3 a at the same time ason the side of the insulating board angled parts 3 d, theirconfiguration and their manufacturing method are similar to those of thefirst embodiment, and accordingly their description is dispensed with.

[0087] Although the foregoing description of the second embodimentreferred to an example in which the second insulating board angled parts3 d are formed adjacent to and continuous from the first insulatingboard angled parts 3 a, the drawn part 3 having the second insulatingboard angled parts 3 d may as well be provided on an edge different fromthe edge of the base 2 on which the drawn part 3 having the firstinsulating board angled parts 3 a is provided.

[0088]FIG. 6 and FIG. 7 illustrate a third preferred embodiment of thepresent invention. In this third embodiment, as in the second embodimentjust described, the drawn part 3 is arranged by having the cables 3 bform the second insulating board angled parts 3 d which are bent in adirection reverse to the first insulating board angled parts 3 a andwider than the cables 3 b.

[0089] The width of the first and second insulating board angled parts 3a and 3 d is formed greater than that of the cables 3 b.

[0090] In the insulating board angled parts 3 a, the first conductivepattern bent parts 4 a are formed and in the cables 3 b, the wiringparts 4 b are formed. Further, the pattern pitch P3 in the conductivepattern bent parts 4 a is greater than the pattern pitch P4 of those ofthe wiring parts 4 b positioned on both sides and close to theconductive pattern bent parts 4 a, and the gap width G3 between theadjacent conductive pattern bent parts 4 a is formed greater than thegap width G4 between those of the wiring parts 4 b positioned on bothsides and close to the conductive pattern bent parts 4 a.

[0091] Furthermore, the pattern width W3 in the conductive pattern bentparts 4 a is formed greater than the pattern width W4 between those ofthe wiring parts 4 b positioned on both sides and close to theconductive pattern bent parts 4 a.

[0092] In the insulating board angled parts 3 d adjacently linked to theinsulating board angled parts 3 a via the cables 3 b, the secondconductive pattern bent parts 4 e are formed, and in the cables 3 bpositioned on both sides of the insulating board angled parts 3 d, thewiring parts 4 b are formed. Further, the pattern pitch P5 in theconductive pattern bent parts 4 e is greater than the pattern pitch P6of those of the wiring parts 4 b positioned on both sides and close tothe conductive pattern bent parts 4 e, and the gap width G5 between theadjacent conductive pattern bent parts 4 e is formed greater than thegap width G6 between those of the wiring parts 4 b positioned on bothsides and close to the conductive pattern bent parts 4 e.

[0093] Furthermore, the pattern width W5 in the conductive pattern bentparts 4 e is formed greater than the pattern width W6 of those of thewiring parts 4 b positioned on both sides and close to the conductivepattern bent parts 4 e.

[0094] In a state in which neither running nor blurring can arise, thepitches P3 and P5 are formed to be equal, and so are the pitches P4 andP6 and the gap widths G3 and G5 and the gap widths G4 and G6.

[0095] The pattern widths W3 and W5 are also formed to be equal, and soare the pattern widths W4 and W6.

[0096] Other aspects of the configuration are the same as theirrespective counterparts in the second embodiment. Therefore, the sameconstituent parts are assigned respectively the same reference numbers,and their description is dispensed with.

[0097] The manufacturing method for this printed circuit board, which isthe third embodiment of the invention, by screen printing isaccomplished using an apparatus shown in FIG. 3. Thus the plurality ofwiring patterns 4 are formed by printing over the insulating board 1 bymoving the squeegee 8 in the direction of arrow A in FIG. 6 and FIG. 7.

[0098] Then, first the connecting parts 4 c are formed by printing, andthen the conductive pattern bent parts 4 a are printed, followed by theprinting of those of the wiring parts 4 b near the conductive patternbent parts 4 a, while on the side of the conductive pattern bent parts 4e, the conductive pattern bent parts 4 e are printed after those of thewiring parts 4 b near the conductive pattern bent parts 4 e are printed.

[0099] Printing in this manner uses on the conductive pattern bent parts4 a side a greater pattern pitch P3 than the pattern pitch P4 of thoseof the wiring parts 4 b positioned on both sides and close to theconductive pattern bent parts 4 a, and the gap width G3 between theconductive pattern bent parts 4 a is greater than the gap width G4 ofthose of the wiring parts 4 b positioned on both sides and close to theconductive pattern bent parts 4 a. Accordingly, even if any running part4 d arises; it is difficult for short-circuiting between the wiringpatterns 4 to arise.

[0100] Furthermore, as a result of printing in this manner, on theconductive pattern bent parts 4 e side where the pattern width W5 of theconductive pattern bent parts 4 e is formed greater than the patternwidth W6 of those of the wiring parts 4 b positioned on both sides andclose to the conductive pattern bent parts 4 e, even if any blurredpart4 f or the like occurs in the conductive pattern bent parts 4 e, thereis more of the residual pattern in the conductive pattern bent parts 4 ethan according to the prior art, and accordingly no wire breaking willarise, resulting in enhanced reliability.

[0101] In the third embodiment of the invention described above, it ispossible to form the wiring patterns 4 by moving the squeegee 8 in thedirection of arrow B in FIG. 6 and FIG. 7.

[0102] Thus, as the squeegee 8 is moved in the direction of arrow B tocarry out screen printing, first the conductive pattern bent parts 4 eare formed by printing, followed by the printing of the wiring parts 4 bclose to the conductive pattern bent parts 4 e, and then the conductivepattern bent parts 4 a are printed after the wiring parts 4 b close tothe conductive pattern bent parts 4 a are printed.

[0103] Printing in this manner uses on the conductive pattern bent parts43 side a greater pattern pitch P5 than the pattern pitch P6 of those ofthe wiring parts 4 b positioned on both sides and close to theconductive pattern bent parts 43, and the gap width G5 between theconductive pattern bent parts 4 e is greater than the gap width G6 ofthose of the wiring parts 4 b positioned on both sides and close to theconductive pattern bent parts 43. Accordingly, even if any running part4 d arises, it is difficult for short-circuiting between the wiringpatterns 4 to arise.

[0104] Printing in this manner uses on the conductive pattern bent parts4 a a greater pattern width W3 than the pattern width W4 of those of thewiring parts 4 b positioned on both sides and close to the conductivepattern bent parts 4 a, and even if any blurring part 4 f or the likearises, there is more of the residual pattern in the conductive patternbent parts 4 a than according to the prior art. Accordingly no wirebreaking will arise, resulting in enhanced reliability.

[0105] Thus this third embodiment of the invention is more flexiblebecause it is adaptable to printing in both directions, that of arrow Aand that of arrow B.

[0106] To add, while the third embodiment of the invention described hasthe second insulating board angled parts 3 d formed adjacent to andcontinuous from the first insulating board angled parts 3 a, the drawnpart 3 having the second insulating board angled parts 3 d may as wellbe provided on an edge different from the edge of the base 2 on whichthe drawn part 3 having the first insulating board angled parts 3 a isprovided.

[0107]FIG. 8 shows an alternative version of the manufacturing methodfor the printed circuit board, which is the third embodiment of theinvention shown in FIG. 6 and FIG. 7. In this version, the squeegee 8 ismoved in the direction of either arrow A or arrow B over a largeinsulating base 11, and a plurality of wiring patterns 4 shown in FIG. 6are formed by printing in the areas indicated by two-dot chain lines,followed by the punching of the base 2 and the drawn part 3 along thefirst and second conductive pattern bent parts 4 a and 4 e and thewiring parts 4 b in the positions indicated by two-dot chain lines toform an insulating board 1 for each set.

[0108] Incidentally, while the foregoing description of this embodimentof the invention referred to has a configuration in which the secondinsulating board angled parts 3 d are formed adjacent to and continuousfrom the first insulating board angled parts 3 a, the drawn part 3having the second insulating board angled parts 3 d may as well beprovided on an edge different from the edge of the base 2 on which thedrawn part 3 like the one shown in FIG. 1 or the drawn part 3 having thefirst insulating board angled parts 3 a is provided.

[0109] However, in a configuration in which individual insulating boards1 are arranged alternately as shown in FIG. 8 and which has theconductive pattern bent parts 4 a and 4 e bent in the reverse directionto each other, both the gap width and the pattern width in theconductive pattern bent parts should be wider than those in the wiringparts.

[0110] To add, in the printed circuit board embodying the invention asdescribed above, the wiring patterns except connecting parts to outsideincluding the connecting parts 4 c and fixed contacts (not shown) may becovered with an insulating resist layer.

[0111] The wiring patterns according to the invention may consist ofsilver or a mixture of silver and carbon, the latter's content beingsmall enough not to affect the electroconductivity of silver.

[0112] The insulating board according to the invention, though aconfiguration comprising the base 2 and the belt-shaped drawn part 3 wasreferred to in the foregoing description, may have a square orrectangular overall shape or consist of only a belt-shaped drawn part.

[0113] Further, the cables 3 b may have a non-linear shape, curvilinearor otherwise.

[0114] As in the printed circuit board according to the presentinvention the gap width G 1 between adjoining first conductive patternbent parts 4 a is greater than the gap width G2 between those of thewiring parts 4 b positioned on both sides and close to the conductivepattern bent parts 4 a, even if any running part 4 d arises in theconductive pattern bent parts 4 a it is difficult for short-circuitingto occur between wiring patterns 4, resulting in enhanced reliability.

[0115] Further, as the pattern pitch PI in the first conductive patternbent parts 4 a is set greater than the pattern pitch P2 of those of thewiring parts 4 b positioned on both sides and close to the conductivepattern bent parts 4 a, there is no need to narrow the pattern width inthe first conductive pattern bent parts 4 a, and accordingly in theabsence of any running part 4 d, too, an appropriate pattern width canbe secured.

[0116] Also the invention can be suitably applied to narrowed spacingbetween wiring patterns 4 along with reductions in the size accompanyingthe advance in the dimensional compression of electronic devices inwhich they are to be used.

[0117] Moreover, as the pattern width W3 in the first conductive patternbent parts 4 a is greater than the pattern width W4 of those of thewiring parts 4 b positioned on both sides and close to the conductivepattern bent parts 4 a, greater freedom can be allowed in the choice ofprinting direction.

[0118] Also, as the wiring patterns 4 are screen-printed in such aprinting direction that the first conductive pattern bent parts 4 a beformed by printing earlier than the wiring parts 4 b, the wiring parts 4b can be patterned following the patterning of the conductive patternbent parts 4 a, resulting in the elimination of the risk of adjacentwiring patterns 4 coming into contact with each other.

[0119] Moreover, the insulating board 1 has the first insulating boardangled parts 3 a and the cables 3 b linked to both ends of these firstinsulating board angled parts 3 a, the width of the first insulatingboard angled parts 3 a is formed greater than that of the cables 3 b,and the plurality of wiring patterns 4 are formed in a state in whichthe first conductive pattern bent parts 4 a are positioned in the firstinsulating board angled parts 3 a and the wiring parts 4 b arepositioned in the cables 3 b, with the result that the insulating board1 is large only in some part of the first insulating board angled parts3 a, which means no obstacle to size compression.

[0120] The wiring patterns 4 have the second conductive pattern bentparts 4 e bent in a direction reverse to the first conductive patternbent parts 4 a and the wiring parts 4 b linked to these secondconductive pattern bent parts 4 e, and the pattern width W1 (W5) inthese second conductive pattern bent parts 4 e is greater than thepattern width W2 (W6) of those of the wiring parts 4 b positioned onboth sides and close to the second conductive pattern bent parts 4 e,with the result that, even if any blurred part 4 f or the like arises inthe conductive pattern bent parts 4 e in the process of formation byprinting, there is more of the residual pattern than according to theprior art, and therefore no wire breaking will arise, resulting inenhanced reliability.

[0121] Also, as the wiring patterns 4 are screen-printed in such aprinting direction that the second conductive pattern bent parts 4 e areformed by printing after the wiring parts 4 b linked to the secondconductive pattern bent parts 4 e are formed by printing, the pattern ofthe conductive pattern bent parts 4 e is formed following the patternformation of the wiring parts 4 b, with the result that the silver paste7 can smoothly permeate the wiring parts 4 b and, even if any blurredpart 4 f or the like arises in the conductive pattern bent parts 4 e,the widened pattern serves to reduce wire breaking.

[0122] Further, as the pattern pitch P5 in the second conductive patternbent parts 4 e is greater than the pattern pitch P6 of those of thewiring parts 4 b positioned on both sides and close to the secondconductive pattern bent parts 4 e, and the gap width G5 in the secondconductive pattern bent parts 4 e is formed greater than the gap widthG6 of those of the wiring parts 4 b positioned on both sides and closeto the second conductive pattern bent parts 4 e, greater freedom can beallowed in the choice of printing direction, resulting in enhancedproductivity.

[0123] The insulating board 1 has the second insulating board angledparts 3 d bent in a direction reverse to the first insulating boardangled parts 3 a and the cables 3 b linked to both sides of these secondinsulating board angled parts 3 d, the width of the second insulatingboard angled parts 3 d is formed greater than that of the cables 3 b,and the plurality of wiring patterns 4 are arranged in a state in whichthe second conductive pattern bent parts 4 e are positioned in thesecond insulating board angled parts 3 d and the wiring parts 4 b arepositioned in the cables 3 b, with the result that the insulating board1 is large only in some part of the first insulating board angled parts3 a, which means no obstacle to size compression.

[0124] Also, as the first insulating board angled parts 3 a and thesecond insulating board angled parts 3 d bent in a direction reverse tothese first insulating board angled parts 3 a are formed adjacentlylinked by the cables 3 b, the freedom of the drawn part 3 can beenhanced, making it possible to provide printed circuit boards adaptableto many different forms.

[0125] It is further made possible to provide a highly reliablemanufacturing method which can effectively prevent short-circuitingbetween the wiring patterns 4 because the plurality of wiring patterns4, having the first conductive pattern bent parts 4 a and the wiringparts 4 b linked to these first conductive pattern bent parts 4 a, areprovided, and the wiring patterns 4 are screen-printed over theinsulating board 1 in such a printing direction that the firstconductive pattern bent parts 4 a are formed by printing earlier thanthe wiring parts 4 b, and the gap width GI between the adjoining firstconductive pattern bent parts 4 a is greater than the gap width G2between those of the wiring parts 4 b positioned on both sides and closeto the first conductive pattern bent parts 4 a.

[0126] It is also possible to provide a manufacturing method capable ofsecuring an appropriate pattern width in the absence of any running part4 d, too, because the pattern pitch P1 in the first conductive patternbent parts 4 a is formed greater than the pattern pitch P2 of those ofthe wiring parts 4 b positioned on both sides and close to the secondconductive pattern bent parts 4 a, thereby eliminating the need tonarrow the pattern width in the first conductive pattern bent parts 4 a.

[0127] It is further possible to provide a manufacturing methodexcelling in the performance of formation by printing even where thereare different conductive pattern bent parts because the wiring patterns4 have the second conductive pattern bent parts 4 e bent in a directionreverse to the first conductive pattern bent parts 4 a, the wiringpatterns 4 are formed by screen printing over the insulating board 1 insuch a printing direction that the wiring parts 4 b linked to the secondconductive pattern bent parts 4 e are formed by printing earlier thanthe second conductive pattern bent parts 4 e so that the pattern widthW1 (W5) in these second conductive pattern bent parts 4 e is formedgreater than the pattern width W2 (W6) of those of the wiring parts 4 bpositioned on both sides and close to the second conductive pattern bentparts 4 e.

[0128] It is also possible to provide a manufacturing method capable ofensuring insulation from adjoining wiring patterns 4 by securing anappropriate pattern width in the absence of any blurred part 4 f, too,because the pattern pitch P5 of the second conductive pattern bent parts4 e is formed greater than the pattern pitch P6 of those of the wiringparts 4 b positioned on both sides and close to the second conductivepattern bent parts 4 e, thereby eliminating the need to narrow the gapwidth in the second conductive pattern bent parts 4 e.

[0129] It is further possible to provide a manufacturing method whichcan enhance the freedom of the choice of the drawing pattern andfacilitate the manufacture of wiring patterns adaptable to manydifferent forms because the wiring patterns are screen-printed over theinsulating board 1 in a state in which the first conductive pattern bentparts 4 a and the second conductive pattern bent parts 4 e adjoiningthese first conductive pattern bent parts 4 a are linked by the wiringparts 4 b.

[0130] It is also possible to provide a manufacturing method capable ofproducing many sets of wiring patterns 4 at a time, resulting inenhanced productivity, because a plurality of sets of the wiringpatterns each consisting of the wiring patterns 4 provided with thefirst and second conductive pattern bent parts 4 a and 4 e and thewiring parts 4 b are formed by screen printing over the large insulatingboard 11.

[0131] It is further possible to provide a manufacturing method capableof producing many insulating boards 1 at a time, resulting in enhancedproductivity, because the large insulating base 11 is punched to formthe insulating boards 1 each having a set of wiring patterns 4 formedfrom a plurality of sets of wiring patterns.

[0132] It is also possible to provide a manufacturing method capable ofreadily producing the drawn part 3 of a complex shape because the largeinsulating base 11 is punched along the first and second conductivepattern bent parts 4 a and 4 e, and pattern formation is carried out ina state in which the first and second conductive pattern bent parts 4 aand 4 e are positioned in the first and second insulating board angledparts 3 a and 3 d of the insulating board 1 and the wiring parts 4 b arepositioned in the cables 3 b linked to the first and second insulatingboard angled parts 3 a and 3 d of the insulating board 1.

[0133] It is further possible to provide a manufacturing methodinvolving no obstacle to size compression and allowing efficientmaterial utilization because the first and second insulating boardangled parts 3 a and 3 d are formed by punching out of the largeinsulating base 11 to be wider than the cables 3 b and accordingly theinsulating board 1 is large only in the first and second insulatingboard angled parts 3 a and 3 d.

What is claimed is:
 1. A printed circuit board having an insulatingboard and a plurality of wiring patterns formed over the insulatingboard by screen printing and provided with conductive pattern bent partsand wiring parts linked to the conductive pattern bent parts, wherein apattern width in the conductive pattern bent parts is greater than thatof the patterns of those of the wiring parts positioned close to and onboth sides of the conductive pattern bent parts.
 2. The printed circuitboard according to claim 1, wherein a pitch of patterns in theconductive pattern bent parts is formed greater than that of thepatterns of those of the wiring parts positioned close to and on bothsides of the conductive pattern bent parts.
 3. The printed circuit boardaccording to claim 1, wherein the wiring patterns are screen-printed insuch a printing direction that the conductive pattern bent parts areformed by printing earlier than the wiring parts.
 4. The printed circuitboard according to claim 1, wherein the insulating board has insulatingboard angled parts and cables linked to both sides of the insulatingboard angled parts, wherein a width of the insulating board angled partsis formed greater than that of the cables, wherein the conductivepattern bent parts are positioned in the insulating board angled parts,and wherein a plurality of the wiring patterns are provided in a statein which the wiring parts are positioned in the cables.
 5. A printedcircuit board having an insulating board and a plurality of wiringpatterns formed over the insulating board by screen printing,comprising: first conductive pattern bent parts; first wiring partslinked to the first conductive pattern bent parts; second conductivepattern bent parts; and second wiring parts linked to the secondconductive pattern bent parts; wherein the first conductive pattern bentparts are bent in a direction reverse to the second conductive patternbent parts, wherein a pattern width in the first conductive pattern bentparts is formed greater than that of the first wiring parts positionedclose to and on both sides of the first conductive pattern bent parts,and wherein a pattern width in the second conductive pattern bent partsis formed greater than that of the second wiring parts positioned closeto and on both sides of the second conductive pattern bent parts.
 6. Theprinted circuit board according to claim 5, wherein the wiring patternsare screen-printed in such a printing direction that the firstconductive pattern bent parts are formed by printing after the wiringparts linked to the first conductive pattern bent parts are formed byprinting.
 7. The printed circuit board according to claim 5, wherein apitch of patterns in the first conductive pattern bent parts is formedgreater than that of the patterns of those of the wiring partspositioned close to and on both sides of the first conductive patternbent parts, and wherein gaps between adjoining ones of the firstconductive pattern bent parts are formed wider than those between thoseof the wiring parts positioned close to and on both sides of the firstconductive pattern bent parts.
 8. The printed circuit board according toclaim 5, wherein the insulating board has first insulating board angledparts bent in a direction reverse to the second insulating board angledparts and cables linked to both sides of the first insulating boardangled parts, wherein a width of the first insulating board angled partsis formed greater than that of the cables, and wherein a plurality ofthe wiring patterns are provided in a state in which the firstconductive pattern bent parts are positioned in the first insulatingboard angled parts and the wiring parts are positioned in the cables. 9.The printed circuit board according to claim 8, wherein the firstinsulating board angled parts bent in a direction reverse to the secondinsulating board angled parts and the second insulating board angledparts are formed adjoining each other, linked by the cables.